
More liquid magma fills the caldera below Yellowstone National Park than previously estimated, according to a new study, but there’s no cause for alarm. Yellowstone still isn’t likely to erupt in a catastrophic way in our or our children’s lifetimes. It’s not even likely to slowly ooze lava anytime soon.
Instead of foretelling an apocalypse, the new study gives a slightly clearer picture of what lies miles below the Earth’s crust. Michael Poland, scientist-in-charge of the Yellowstone Volcano Observatory, likens it to the Hubble Space Telescope. The lens on the telescope was blurry. Astronauts replaced that lens and suddenly everyone had a better view of space. A better view didn’t change space, it just let us see it more clearly.
It may seem strange for researchers to emphasize that a groundbreaking study published in a prestigious journal like Science doesn’t change the outcome of something as consequential as a volcano, but that’s the point. For a frequently overhyped system such as Yellowstone, researchers mostly want people to know that the risk is quite low, but the science is still quite interesting.

Yellowstone National Park’s Grand Prismatic Spring, seen here from the boardwalk. (NPS/Jacob W. Frank)
The Yellowstone system has a long history of spectacular explosions. The current landscape was formed largely by three major events, the first about 2.1 million years ago, then 1.3 million years ago, then 631,000 years ago. Each of those eruptions was significant enough to blanket much of the western half of the U.S. in ash. More than 20 lava flows have pushed up from the ground and spread out over the landscape since the last explosion, the most recent being 70,000 years ago. That lengthy calm does not mean Yellowstone is primed to blow again.
It mostly means Yellowstone doesn’t do all that much all that often, Poland said, at least when it comes to volcanic activity.
The challenge with truly understanding what’s underneath Yellowstone or any other volcanic system is that we can’t see it. So researchers are left with assumptions and the best data they can gather. Fortunately, more data has been collected on Yellowstone than almost any other volcanic system in the world, which is where Ross Maguire, an assistant professor at the University of Illinois, comes in.
Maguire is the lead author on the new study published Dec. 1 in the journal Science called “Magma accumulation at depths of prior rhyolite storage beneath Yellowstone Caldera.”
Broken down in simple terms, he and his team used a supercomputer to analyze seismic waves that constantly weave through the earth’s crust. In some ways it’s like a CT scan on a human. Waves travel at one speed through solids and slow down when they hit liquids, allowing Maguire and others to get a better picture.
Previous studies estimated about 5% to 15% of the mass beneath Yellowstone was liquid magma. The new research shows it’s likely 16% to 20%. That increase doesn’t represent a significant change, but a more nuanced understanding.
Most importantly, the research continues to illustrate that what lies beneath Yellowstone is not some enormous tank or reservoir of liquid magma ready to burst through the surface. It’s not a ticking time bomb, said Kari Cooper, a professor at the University of California, Davis, and one of the world’s leading volcanologists who wrote a perspective piece to accompany the paper. Yellowstone’s magma chamber is really more of a great chamber of mush.
She likens it to a snow cone where the ice in the snow cone is rock and the liquid magma is the delicious sugary syrup mixed in. In some spots the ice is melted and the liquid pools. In most areas, it’s distributed evenly. Researchers can only guess what could cause that snow cone to eventually be melty enough to produce lava that rises to the surface. The physics of it, Cooper said, “is complicated.”
Regardless, anything that could produce that kind of reaction in a system as large as Yellowstone would be major.
“Communities in Gardner in West Yellowstone, Jackson and Cody, they would feel it, they would see it in the changes in the geyser activity and the gas emissions,” said Poland. “The ground would be rising. It would be pretty obvious.”
Why does a more accurate picture matter? Because the more we learn about volcanic systems, the more we understand their behavior and can interpret their signs, Cooper said. While each volcano certainly has its own personality — Hawaii’s currently erupting Mauna Loa, for example, has spewed 34 times since its first recorded eruption in 1843 — research like Maguire’s can also teach us more about volcanoes in general.

Rime ice and sun dogs create a winter scene in Yellowstone National Park’s Upper Geyser Basin in December 2015. (Neal Herbert/National Park Service)
“All these studies of what’s going on below the surface are important because they allow us to interpret the monitoring signals that we’re getting from the surface,” said Cooper. “In order to say — ‘OK, what does this seismic pattern, or earthquake pattern or deformation pattern mean?’ — you have to have an image in your head of what could be happening below the surface.”
For Maguire, it’s about increasing knowledge about the long-term evolution of our planet.
It also shows how far humans have come in our ability to use supercomputers to understand the Earth’s depths, which means we can continue to develop clearer pictures of what is there.
As far as risk goes, Poland has advice for anyone feeling nervous about the volcano.
Plenty of hazards exist in Yellowstone that have nothing to do with the caldera. The plates in the area are capable of earthquakes with a magnitude of 7 or greater. The hydrological system can produce geysers that spew mud and rocks and leave craters up to a mile wide. And none of the daily variation in geysers and earthquakes signal any real change in the volcano itself.
“I think that there’s a disservice done by the documentaries and the clickbait and the YouTube channels that focus on this thing that’s not going to happen, versus some of the things that could happen on human timescales like large earthquakes and steam explosions,” Poland said.
WyoFile is an independent nonprofit news organization focused on Wyoming people, places and policy.
Part of me wishes that all scientists and others of influence would concentrate on some that is happening, and has consequences……….climate change and global warming. Seems like that’s an area where the pace needs to quicken and more pressure needs to be put on our leaders.
Gary, shut up
Love the article
Gary, take a look at what volcanoes do when they erupt.You want to talk about climate change! Mother earth still is the biggest polluter on her planet. Compared to what she dishes out, we are nothing.
Hype sells, and scaring people is the politicians’ oldest trick. If you tell people the truth, that things are happening very slowly in human time scales, they aren’t panicky enough to actually do anything. People don’t worry enough if you tell them sea levels “might” rise 12 inches in the next 100 years, so you have time to build a dike. They also won’t panic if you tell them there are actually positive benefits of a warmer planet, like longer growing seasons, more food production, less deaths from cold exposure, or the fact that cold kills many times more people than heat every year. No, you have to scare people to get them to do what you want. For their own good, of course.
They can watch the series Snowpiercer…..now THAT would be a freakin’ nightmare earth future!
Humans by nature are lazy. Like you said, you have to shock them into doing something.
I’ll say, even if there was a remote chance of a VEI 8, or super eruption, i doubt the government leaders would tell us, they would prolly say it would be something the size of Helens, or Vesuvius in Pompeii back in 79AD. They would tell us have stuff for like 3-6 days and stay indoors. When the government tells us to be calm and don’t panic, that’s when you run. Yellowstone will erupt, not in our lifetime, or the next 1000 years, who knows. But never bad to be wary and pay attention to the sciences and mother earth.
When Yellowstone erupts, there won’t be anywhere for people to hide. We are all dead. Just depends on if it’s immediate or a few months. I’d rather be right next to it. People will suffer
Milankovitch cycles every 23,000 years. You won’t hear a politician bring them up, because there is nothing that can be done and no way to milk the common citizens of their tax dollars.
I agree with some of the things that politicians want to the point we shouldn’t destroy the natural beauty of the planet and leave it better for or children.
I just think they are a lot more about the dollars than cost effective ideas and results